/**
 * Test basic read committed functionality, including:
 *  - Writes with writeConcern 'majority' should be visible once the write completes.
 *  - With the only data-bearing secondary down, committed reads should not include newly inserted
 *    data.
 *  - When data-bearing node comes back up and catches up, writes should be readable.
 */

load("jstests/replsets/rslib.js");  // For startSetIfSupportsReadMajority.

(function() {
"use strict";

// Set up a set and grab things for later.
var name = "read_committed";
var replTest = new ReplSetTest({name: name,
                                nodes: 3,
                                nodeOptions: {enableMajorityReadConcern: ''}});

if (!startSetIfSupportsReadMajority(replTest)) {
    jsTest.log("skipping test since storage engine doesn't support committed reads");
    return;
}

var nodes = replTest.nodeList();
replTest.initiate({"_id": name,
                   "members": [
                       { "_id": 0, "host": nodes[0] },
                       { "_id": 1, "host": nodes[1], priority: 0 },
                       { "_id": 2, "host": nodes[2], arbiterOnly: true}]
                  });

// Get connections and collection.
var primary = replTest.getPrimary();
var secondary = replTest.liveNodes.slaves[0];
var secondaryId = replTest.getNodeId(secondary);
var db = primary.getDB(name);
var t = db[name];

function doDirtyRead() {
    var res = t.runCommand('find', {"readConcern": {"level": "local"}});
    assert.commandWorked(res);
    return new DBCommandCursor(db.getMongo(), res).toArray()[0].state;
}

function doCommittedRead() {
    var res = t.runCommand('find', {"readConcern": {"level": "majority"}});
    assert.commandWorked(res);
    return new DBCommandCursor(db.getMongo(), res).toArray()[0].state;
}

// Do a write, wait for it to replicate, and ensure it is visible.
assert.writeOK(t.save({_id: 1, state: 0}, {writeConcern: {w: "majority", wtimeout: 60*1000}}));
assert.eq(doDirtyRead(), 0);
assert.eq(doCommittedRead(), 0);

replTest.stop(secondaryId);

// Do a write and ensure it is only visible to dirty reads
assert.writeOK(t.save({_id: 1, state: 1}));
assert.eq(doDirtyRead(), 1);
assert.eq(doCommittedRead(), 0);

// Try the committed read again after sleeping to ensure it doesn't only work for queries
// immediately after the write.
sleep(1000);
assert.eq(doCommittedRead(), 0);

// Restart the node and ensure the committed view is updated.
replTest.restart(secondaryId);
db.getLastError("majority", 60 * 1000);
assert.eq(doDirtyRead(), 1);
assert.eq(doCommittedRead(), 1);


}());
